Apparatus for swaging a collar onto an externally grooved member

ABSTRACT

A manually held hydraulically and pneumatically powered swaging tool for swaging a collar ( 35 ) onto a grooved or threaded bolt ( 36 ) includes jaws ( 39 ) having internal grooves ( 40 ) which match the groove ( 20 ) on the bolt. The jaws ( 39 ) are openable to receive the projecting portion of the bolt ( 36 ) and are closable to engage the bolt. An anvil ( 26 ) outside the jaws is axially movable by hydraulic means forwards over the jaws to lock them into engagement with the bolt, and then to force the anvil over the collar ( 35 ) to swage it to the bolt. The tool includes a detection rod ( 40 ) for detecting when the bolt ( 36 ) has been fully inserted into the open jaw ( 39 ). Thereby to initiate closure of the jaws by pneumatic means. Also, initial forwards movement of the anvil ( 26 ) is arranged to move the jaws axially forwards by an appropriate small distance, if this is necessary to axially align the grooves ( 40 ) on the jaws correctly in relation to the groove ( 20 ) on the bolt to enable closure of the jaws.

The invention relates to apparatus for swaging a deformable collar ontoan externally grooved member. The grooves may be in the form of a thread(when the grooved member comprises a bolt or stud). Alternatively thegrooves may extend circumferentially around the member (when the membercomprises a lockbolt).

Such a member is hereinafter referred to as “an externally groovedmember of the type defined”.

The invention provides, in one of its aspects, apparatus as claimed inappended claim 1. Further preferred features of this invention are asclaimed in claims 2 to 8.

An embodiment of the invention will now be described by way of example.This is a hydraulically-powered hand-held tool for swaging a collar ontoa lockbolt. In the accompanying drawings:

FIG. 1 is a longitudinal axial section through the tool, showing itsmechanism in the rest position (i.e. unactuated);

FIGS. 2, 3 and 4 are similar to FIG. 1 and show the mechanism insuccessive stages of operation;

FIG. 5 is a perspective view of the parts of the tool axially exploded,by way of illustration.

In these drawings, some parts of the tool which are common in the art,and are not directly parts of the present invention, are not shown.

Referring first to FIGS. 1 and 5, the tool of this example includes ahydraulic cylinder casing 11 defining a hydraulic cylinder 12 withinwhich reciprocates a double-acting hydraulic piston 13. To the rear end(i.e. the right hand end as shown in the Figures) of the underside ofthe cylinder casing 12 is attached a handle 14. This handle carries twohydraulic line connectors 15,15 to which hydraulic hoses (not shown) areconnected. By means of passages (not shown) in the handle 14 and casing11, one of the connectors 15 feeds hydraulic fluid to and from one sideof the piston 13 under the control of a trigger 16, and the otherconnector 15 similarly feeds hydraulic fluid to and from the oppositeside of the piston 13. The handle 14 carries the trigger 16. The triggeris biassed into its outer or released position, in which it feedshydraulic fluid under pressure to the rear of the piston 13. When thetrigger is pressed against its biassing, it changes the feed ofhydraulic fluid under pressure to the front of the piston 13.

The rod 17 of the piston 13 extends forwardly through the front plate 18of the cylinder 11. To the forwards end (i.e. to the left as shown inthe Figures) of the hydraulic cylinder 11 is threadedly attached a body19 containing a cylindrical internal bore 21. At the front end of thebody 19 is mounted a nosepiece tube 22, which can reciprocate to alimited extent with respect to the body 19. Thus the rear of the tube 22has a radially extending flange 23 received within an enlargement 24 atthe front of the body bore 21. The front end of the enlarged bore 24 iscovered by a threadedly-engaged cap 25, through which the nosepiece tube22 protrudes. As shown in FIG. 1, the axial length of the boreenlargement 24 is greater than the thickness of the nosepiece flange 23,thus allowing the nosepiece tube 22 to

reciprocate axially to a limited extent. The forward end of the tube 22carries an anvil 26 which is of annular form and made from hardenedsteel. The front end of the anvil bore 27 is formed with a chamfer ortaper 28, which is of appropriate size and shape to swage over the endof a bolt collar 35. The rear end of the anvil tube 26 is threadedlyattached to the front end of the nosepiece tube 22. Between the two isan annular cam plate 29. The cam plate 29 comprises two semi-circularhalves, to enable the cam to be inserted into the appropriate place whenthe tool is assembled.

To the front end of the piston rod 17 is threadedly attached a pistontube 31, which extends forwardly through the body bore 21 and thenosepiece tube 22. The piston tube 31 has a slight radial clearance withrespect to the body bore 21 and the interior of the nosepiece tube 22(this may not be apparent from the drawings), sufficient to enablecompressed air to flow along it for the purposes which will be describedbelow. To the front end of the piston tube 31 is threadedly attached ajaw-support tube 32, which has an outwardly extending flange 33 abouthalfway along its length. Radially outside the jaw support tube 32 andradially inside the front end part of the nosepiece tube 22 are a set ofjaws comprising three jaw members 34, 34, 34. Each jaw member has across-section of a 120 degrees angled sector, so that the three jawmembers fit together to form an elongated generally cylindrical shapedset of jaws. Each jaw member 34 has a recess 42 which receives, withsome clearance, the appropriate part of the flange 33. The jaw membersare urged rearwardly with respect to the support tube 32 by means of ahelical spring 49.

This tool is designed to swage a deformable collar 35 onto an externallygrooved member of the type defined which is in the form of a bolt 36with grooves 20, which is inserted through an aperture 37 in a workpiece38. Accordingly the front portion of each jaw member 34 has an internalenlargement recess 39, the three recesses together providing asubstantially cylindrical socket 41 to receive the end portion of thebolt 36. Each recess face is formed with grooves 40 (only a few of whichare shown in FIG. 1 for clarity of illustration) which are complementaryin shape to the grooves 20 on the bolt 36 so as to be able to engagewith them. The part of each jaw member 34 between its flange 33 and itsrecess 39 is of slightly larger diameter than the exterior of thesupport tube 32 over which it is positioned, so that each jaw member canrock slightly about the flange 33, so as to open the jaws by movingslightly radially apart from each other the recesses 39 to allow the endof the bolt to enter the jaws. The jaws can then be closed to engage thebolt by the interengagement of the grooves on the jaws 34 with thegrooves on the bolt 36. The jaws are normally held open by a radiallycontracting spring 48 around the rear ends of the jaw members and radialcompression springs 30 in front of the flanges 33S.

The forward ends of the jaw members, around the recess 39, are radiallythickened. This thickening has a front face 43 to contact the end faceof the bolt collar 35, and a tapered rear slope 44 which co-operateswith the chamfer 28 at the front end of the anvil bore. Further backeach jaw member has an external recess 45 which accommodates theradially innermost part of the cam plate 29. The forward end of thisrecess has a rearwards-facing chamfer 46 which co-operates with theinner front edge of the cam plate 29. The recess 45 is slightly longerthan the thickness of the cam plate 29, and has a rear face which canengage the rear face of the cam plate 29, there thus being a smallamount of axial lost motion between the cam plate 29 and the jaw members34.

Means for detecting when a bolt 36 has fully entered into the jawsrecess 39 includes an elongated detector rod 51 positioned axiallywithin the piston tube 31. The rear end of the detector rod has anenlarged head 52, against which presses a helical spring 53. This urgesthe detector rod forwards with respect to the piston tube 31, so thatits head 52 seals the inner end of a radial bore 54 in the piston tubelocated towards its rear end. In this position the front end portion 55of the detector rod projects slightly into the jaw recess 39, as shownin FIG. 1. There is sufficient radial clearance between the detector rod51 and the piston tube 31 to allow compressed air to flow along thisclearance as far as another radial bore 56 further forwards along thepiston tube, which connects this clearance with the radial clearancebetween the piston tube 31 and the nosepiece tube 22. This clearanceconnects to the rear side of the nosepiece flange 23 (i.e. the space 62indicated in FIG. 3). An external air pressure feed hose (not shown) isconnected via connector 57 with the space 61 in the bore enlargement 24in front of the nosepiece flange 23. Another radial bore 58 through thetool body 19 connects the clearance between the bore 21 and the pistontube 31 with a second external air hose (not shown) via a connector 59.Various O-ring seals are provided at appropriate positions along thebody bore 21, as shown in FIG. 1, to seal the ends of the clearance toprevent the escape of pressure air, and to prevent the passage of airalong the clearance between the radial bores 56 and 58. Thus air underpressure supplied through the connector 59 will be shut off from therear of the nosepiece flange 23 when the air valve means provided by thedetector rod head 52 is closed, i.e. when the detector rod 51 is in itsforwards position, as shown in FIG. 1.

The way in which the tool operates will now be described with referenceto FIGS. 1 to 4.

When the tool is in the rest position as illustrated in FIG. 1, with thetrigger 16 not depressed, hydraulic pressure is fed to the rear of thepiston 13 so that the piston is held in its forwards position, and thejaws 34, 34, 34 are in their open position. Since there is no boltwithin the jaw recess 39, the detector rod 51 is in its forwardsposition so that the valve means provided by its head 52 is closed. Thisprevents air pressure from being supplied by the rearward air hose 59from reaching the rear of the nosepiece flange 23.

The operator, holding the tool in his hand by means of its handle 14,offers up the tool to the projecting end of the bolt 36 so that thelatter enters the jaw socket 41. He pushes the tool forwards so that thejaw front face 43 contacts the front end face of the collar 35 andpushes the collar along the bolt until the other end of the collarcontacts the front face of the workpiece 38. The bolt in the workpiecehas been selected so that, when this occurs, the front end of the boltwill have contacted the front end 55 of the detector rod 51 and willhave pushed the rod sufficiently far backwards to unseal the inner endof the radial bore 58. This is the position illustrated in FIG. 2. Thefront end of the bolt is very close to, or in contact with, the frontend of the jaw support tube 32.

As previously described, this allows compressed air to be fed to therear of the nosepiece flange 23. Since the area of the rear face of thenosepiece flange 23 is substantially greater than the area of its frontface, the forwards force due to the air pressure on its rear face issubstantially greater than the rearwards force on its front face, andthe nosepiece tube 22 moves forwards, until the front face of its flangecontacts the cap 25, as illustrated in FIG. 3.

As the nosepiece tube 22 and the anvil 26 move forwards with respect tothe jaws (the operator is still pushing the tool towards the bolt), thejaw members 34 are urged to close together by two successive thrusts.

Firstly, the inner front edge part of the cam plate 29 engages therearwards-facing chamfer 46 of the recess 45 on the jaw members. Thisurges the jaws to close together. If the grooves on the jaw recesses 39are not accurately aligned with those on the bolt 36 (that is to say, ifthe crests of the grooves on the jaws are not aligned axially of thebolt with the valleys of the grooves on the bolt so that the former canimmediately enter the latter), so that the jaws cannot close onto thebolt, the axial force applied by the cam plate 29 to the jaw members 34increases. This pushes the jaw members along the bolt by a smalldistance sufficient to align the crests of one set of grooves with thevalleys of the other set of grooves, so that the jaws can close togetherto engage the bolt by interengagement of the two sets of grooves.

If the grooves on the jaws are aligned with those on the bolt, theinitial engagement between the cam plate 29 and the chamfer 46 on thejaws urges the jaws radially inwardly, without any adjustment of theiraxial position, to engage the bolt.

Secondly, the anvil bore chamfer 28 engages the rear slopes 44 on thefront exterior of the jaw members. This locks the jaw members together,in the position in which they are locked onto the grooves in the bolt36, as illustrated in FIG. 3.

The operator now presses the tool trigger 16. This applies hydraulicfluid pressure to the front of the piston 13 and removes hydraulicpressure from its rear. This applies an increasing high force to theanvil 26, which is sufficient to overcome the forwards pneumatic forceon the nosepiece flange 23, so that the tool body 19 moves forwardsuntil the rear end of its bore 24 contacts the rear face of the flange23. The reaction to the force on the anvil is supported by the bolt 36,and the anvil moves axially over the collar and swages it to the bolt.The anvil locks the jaws together against the radially outwards force onthem from the collar as it is compressed by the anvil. The fully swagedposition is shown in FIG. 4.

The operator now releases the trigger 16, so that hydraulic fluidpressure is switched back to the rear face of the hydraulic piston 13,and the anvil is thereby retracted back along the jaws, therebyreleasing them from the swaged collar.

The invention is not restricted to the details of the foregoing example.

1. Apparatus for swaging a collar onto an externally grooved memberhaving grooves in the form of a thread or grooves which extendcircumferentially around the member, which apparatus comprises: jawmeans which are openable to receive the projecting end portion of such agrooved member on to which a collar has been placed, the jaw means beinginternally grooved and being closable so as to engage the groovedmember; swaging means radially outside the jaw means and axially movablewith respect thereto, whereby when the jaw means is closed and engagesthe grooved member, and an appropriate axial force is applied to theswaging means with respect to the jaw means, the swaging means is forcedforwardly over the collar to swage it into engagement with the groovesof the grooved member; characterized by the apparatus includingautomatic axial position adjustment means for automatically making minoraxial adjustment of the position of the jaw means, if necessary, tocorrectly align its grooves with the grooves on the grooved member,thereby to enable closure of the jaw means to engage the grooved member.2. Apparatus as claimed in claim 1, in which the automatic positionadjustment means is provided by radially outward projections on the jawmeans and radially inward projections on the axially movable swagingmeans, such that if the two sets of grooves are misaligned with eachother so that, when the swaging means advances along the jaw means, thejaw means is prevented from engaging with the grooved member, theradially inward projections on the swaging means engage the radiallyoutward projections on the jaw means and thereby push the jaw meansaxially forwards with respect to the grooved member, thereby tocorrectly align the two sets of grooves as aforesaid.
 3. Apparatus asclaimed in claim 1, which apparatus also comprises detection means fordetecting when the grooved member is fully entered into the open jawmeans and thence initiating closure of the jaw means to engage thegrooved member as aforesaid.
 4. Apparatus as claimed in claim 3, inwhich the detection means comprises an air valve.
 5. Apparatus asclaimed in claim 4, in which the air valve is biased closed and isopened by the presence of the grooved member fully entered into the jawmeans.
 6. Apparatus as claimed in claim 4, in which the jaw means isbiased into the open position, and is closed by the application of airpressure admitted by the opening of the air valve.
 7. Apparatus asclaimed in claim 6, in which the jaw means is biased into the openposition by resilient means, e.g. an O-ring and/or spring.
 8. (canceled)